1. Field of the Invention
The present invention generally relates to a pilomotor effect stimulating device and method for artificially producing stimulation of the arrector pili muscles of the skin to produce goosebumps and raise body hairs, and is particularly concerned with an electronic pilomotor effect stimulating device which may be used as a shaving aid.
2. Related Art
Both electronic and non-electronic shaving devices are commonly used for removing hair from various parts of the body, including facial hair for men, as well as arm, leg and underarm hair. One objective in shaving is to achieve a smooth shave removing hair down to the skin level, while not causing damage or irritation to the skin. One problem is that hair often lies relatively flat against the skin, so that the shaving device slides over some hair without cutting it. Users often try to overcome this problem by applying extra pressure to the skin, passing the shaver over the skin several times, or trying to alter the hair position relative to the blade by manually stretching the skin, facial muscle motion, or head movement. All of these actions can increase the risk of skin damage or irritation.
One technique proposed in the past for alleviating shaving irritation and inefficiency has been to apply various topical liquids or lotions to the area to be shaved, as a pre-treatment, so as to soften the hair or dry the skin so as to raise the hairs. Another shaving aid pre-treatment involves chemical stimulation of the skin to produce the so-called pilomotor effect, as described in U.S. Pat. No. 4,853,216 of Koslo et al. and U.S. Pat. No. 4,980,159 of Koslo. The pilomotor effect involves the pilomotor or arrector pili muscles of the skin which shorten when stimulated, producing “goose bumps” and causing the hair to rise to a more upright position. This effect may occur when a person is cold or experiencing emotions such as fear. It can also be produced by certain chemicals, known as alpha adrenergic receptor stimulants, when applied to the skin, as described in the cited patents. The compositions described in these patents may be applied to hair covered areas of the skin prior to shaving, causing the hair to stand up and making it easier to cut hair at a level closer to the skin.
It is also known that electrical excitation and nerve stimulation of the arrector pili muscles causes the muscles to contract and the hair to stand up for a certain time period (See The Response of the Isolated Skin of Rats to Drugs and Electrical Stimulation, by K. Hellman, Brit. J. Pharmacol. (1963, 21, 331-338), and this technique has been used in a laboratory setting for research purposes.